Hemoglobin Levels as a Marker of Arrhythmia Recurrence After Atrial Fibrillation Ablation

ABSTRACT Background Low hemoglobin (Hb) is associated with hemodynamic stress and adverse cardiac remodeling. However, its clinical significance for arrhythmia recurrence after atrial fibrillation (AF) ablation remains unclear. Methods We retrospectively studied 2202 patients undergoing AF ablation between 2014 and 2024 (radiofrequency ablation [RFA]: n = 1606; cryoballoon ablation [CBA]: n = 596). In the RFA cohort, patients were stratified by Hb quartiles, and the lowest quartile cut‐off (Hb < 12.4 g/dL) was applied to the CBA cohort. The primary endpoint was AF or atrial tachycardia recurrence beyond a 90‐day blanking period. Results In the RFA cohort, low Hb was associated with a higher risk of arrhythmia recurrence after the index procedure (adjusted HR 1.33, 95% CI 1.07–1.65) and after multiple procedures (adjusted HR 1.57, 95% CI 1.22–2.02). No significant association was observed in the CBA cohort (adjusted HR 1.03, 95% CI 0.68–1.54). The interaction between Hb level and ablation modality was not statistically significant ( p for interaction = 0.177). In the pooled analysis, low Hb was independently associated with arrhythmia recurrence in the total population (adjusted HR 1.24, 95% CI 1.03–1.50) and in patients with non‐paroxysmal AF (adjusted HR 1.43, 95% CI 1.11–1.85), but not in those with paroxysmal AF (adjusted HR 1.06, 95% CI 0.80–1.39). Conclusions Lower Hb levels were associated with an increased risk of arrhythmia recurrence. The association differed according to AF type, suggesting that low Hb may reflect an adverse atrial substrate rather than a procedural effect.